One processing step in the fabrication of semiconductor products is the dicing of a substrate upon which a plurality of semiconductor devices is fabricated. Generally, circular saws are used for this dicing process. Known configurations of circular saws used in the semiconductor industry include a plurality of circular blades ganged onto a blade assembly, which dice along a plurality of parallel lines simultaneously and at predetermined spacings.
A problem encountered with the known dicing process is that cut material, or detritus, sprays in many directions. The spray of the detritus exposes workers to safety hazards, and creates a messy work environment. To overcome these problems, covers have been installed over the ganged blade assemblies. With specific reference to FIGS. 1a-1b, there is shown a gang blade assembly 10 that includes a blade device 20 and a cover 12. The cover 12 extends around more than half of the circumference of the blade device 20 and includes a top side 13, a trailing side 14 and a leading side 15. The blade device 20 includes a hub 24 and a plurality of parallel spaced blades 22. As illustrated, the device 20 rotates in a direction A, although the device 20 may instead rotate in an opposite direction. The trailing side 14 may extend downwardly farther than the leading side 15.
In some instances an additional deflector may also be used, as shown in FIGS. 2a-2b. FIGS. 2a-2b illustrate a gang blade assembly 110 which differs from the gang blade assembly 10 in that it includes a deflector 16 extending off from the trailing side 14 of the cover 12. The deflector 16, along with the trailing side 14, alters the trajectory of the detritus from the dicing process and inhibits the detritus from being thrown in various upward directions.
Nonetheless, the gang blade assemblies 10, 110 have a disadvantage. The speed of rotation of the blade device 20 creates an air flow which lifts portions of the detritus within the cover 12 where it can contact with the blades 22. Further, the detritus often is deposited in front of the blades, and this loose debris can also contact the blades 22. Such contact may inflict damage on the blades 22, forcing premature replacement or repair of the gang blade assembly 10, 110 or of the blade device 20.
There is therefore a need for a protective assembly which mitigates collection and build up of detritus within the cover 12.